[Curmudgel]

Yes. Keyboards with thumb clusters, e.g. one made by Maltron or Kinesis, make key chords as natural as pressing a single key on a regular keyboard.

[pmoriarty]

There's also the King's Assembly.[1]

[1] - https://www.kickstarter.com/projects/70308014/kings-assembly...

[eikenberry]

http://solidartlabs.com/

Looking forward to reading some reviews once they are available. They look very promising.

[dcolgan]

Using Sharpkeys (http://www.randyrants.com/2011/12/sharpkeys_35.html) I remap Alt to be Ctrl, the Windows key to be Alt, and Ctrl to be the Windows key. Especially on laptop keyboards, the normal Alt keys are easily accessible to thumbs, and this eliminates the awkward hand curling caused by pressing the normal Ctrl with your pinky without needing a special keyboard. I also swap backspace and caps lock.